Heat exchanger

ABSTRACT

A heat exchanger for exchanging heat with gas made to flow in a flow direction is disclosed. The heat exchanger is provided with: a plurality of plates each having a first side and a second side; a plurality of tubes configured to conduct a thermal medium, the tubes penetrating the plates and being arranged in parallel with each other and on a plurality of planes perpendicular to the flow direction, wherein the tubes on each plane are disposed adjacent to gaps between the tubes on any of adjacent planes so as to form a plurality of serpentine flow lines among the tubes; and a plurality of bridges projecting on the first sides of the plates, the bridges being respectively arranged to be perpendicular to the serpentine flow lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application Nos. 2006-077169 (filed on Mar.20, 2006), 2006-012258 (filed on May 15, 2006), and 2006-012259 (filedon May 15, 2006); the entire contents of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger for exchanging heatbetween gas and a thermal medium.

2. Description of the Related Art

Heat exchangers are utilized in various uses. A heat exchanger isprovided with a plurality of tubes for conducting a thermal medium and aplurality of fins respectively projecting from the tubes. Any gassubject to heat exchange is pressurized to flow through spaces among thetubes and the fins so as to exchange heat with the thermal medium. Forimprovement of efficiency of the heat exchange, dimensions of the tubesand the fins are the subject of research.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a heat exchanger whichimproves efficiency of heat exchange.

According to a first aspect of the present invention, a heat exchangerfor exchanging heat with gas made to flow in a flow direction isprovided with: a plurality of plates each having a first side and asecond side; a plurality of tubes configured to conduct a thermalmedium, the tubes penetrating the plates and being arranged in parallelwith each other and on a plurality of planes perpendicular to the flowdirection, wherein the tubes on each plane are disposed adjacent to gapsbetween the tubes on any of adjacent planes so as to form a plurality ofserpentine flow lines among the tubes; and a plurality of bridgesprojecting on the first sides of the plates, the bridges beingrespectively arranged to be perpendicular to the serpentine flow lines.

According to a second aspect of the present invention, a heat exchangerfor exchanging heat with gas made to flow in a flow direction isprovided with: a plurality of plates each having a first side and asecond side; a plurality of tubes configured to conduct a thermalmedium, the tubes penetrating the plates and being arranged at an evenpitch in parallel on a plurality of planes perpendicular to the flowdirection, wherein the tubes on each plane are respectively deviated ina lateral direction with respect to the tubes on any of adjacent planesby half of the pitch of the tubes and the half of the pitch is notgreater than diameters of the tubes; and a plurality of bridgesprojecting on the first sides of the plates, the bridges beingrespectively arranged to be perpendicular to the serpentine flow lines.

According to a third aspect of the present invention, a heat exchangerfor exchanging heat with gas made to flow in a flow direction isprovided with: a plurality of plates each having a first side and asecond side; a plurality of openings formed on the plates and arrangedin a plurality of rows perpendicular to the flow direction, wherein theopenings in each row are disposed adjacent to gaps between the openingsin any of adjacent rows; a plurality of bridge groups respectivelyprojecting on the first sides of the plates and being disposed at thegaps, each of the bridge groups including a plurality of bridgesperpendicular to the flow direction and arranged in a row along the flowdirection, a first pair of sub-bridges disposed on an upstream end ofthe row with respect to the flow direction and slanted from a center toboth sides of the first pair toward the flow direction, and a secondpair of sub-bridges disposed on a downstream end of the row with respectto the flow direction and slanted from both sides to a center of thesecond pair toward the flow direction; and a plurality of tubesconfigured to conduct a thermal medium, the tubes respectivelypenetrating the openings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross sectional view of a heat exchanger inaccordance with an embodiment of the present invention;

FIG. 2 is a side view of the heat exchanger;

FIG. 3 is a sectional view of the heat exchanger taken along a line A-Aof FIG. 1;

FIG. 4 is a perspective view of a plate applied to the heat exchanger;

FIG. 5 is a plan view of the plate;

FIG. 6 is a sectional view of the plate taken along a line B-B of FIG.5; and

FIG. 7 is a sectional view of the plate taken along a line C-C of FIG.5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be described hereinafterwith reference to the appended drawings.

A heat exchanging unit 17 of the present embodiment is used in a housingsuch as one shown in FIG. 1. The housing is provided with a cylinder 14and flanges 15, 16 fixed at both ends thereof for air-tightening. Theexteriors of the flanges 15, 16 are further enclosed by walls, whichrespectively define fluid rooms 23, 24. The heat exchanging unit 17 isprovided with a plurality of tubes 18 running along an axis of thecylinder 14, which liquid-tightly penetrate the flanges 15, 16 and haveopenings at both ends to communicate with the fluid rooms 23, 24.

The heat exchanging unit 17 is further provided with a plurality ofplates 21, which the tubes 18 penetrate. The plates 21 standsubstantially vertical to the axis of the cylinder 14 and are arrangedto have even intervals therebetween.

Referring to FIG. 2, the fluid room 23 is liquid-tightly partitionedinto two sub-rooms 23 a, 23 b by a partition 25. An inlet port 26 islinked with the sub-room 23 a and an outlet port 27 is linked with thesub-room 23 b, thereby a thermal medium such as a cooling water iscapable of flowing in and out of the fluid room 23. The thermal mediumflowing through the inlet port 26 into the sub-room 23 a further flowsthrough some of the tubes 18 and then reaches the opposite fluid room24. Further, the thermal medium in the fluid room 24 flows through therest of the tubes 18, reaches the sub-room 23 b, and are then exhaustedout of the outlet port 27.

The cylinder 14 has a partition 28 therein, which runs along the axis,to partition the interior thereof into a gas migration chamber 29 andthe rest as shown in FIG. 3. The rest of the interior is furtherpartitioned into a gas inflow chamber 32 and a gas outflow chamber 33 bya partition 31 provided at an axial middle of the interior of thecylinder 14 as shown in FIG. 1. The cylinder 14 is provided with a gasinflow port 33 and a gas outflow port 35 to respectively communicatewith the gas inflow chamber 32 and the gas outflow chamber 33.

Gas subject to heat exchange, such as air to be cooled, is made to flowinto the gas inflow port 34 by any gas feeding means such as a rotatingfan or a pump. The gas flows through the gas inflow port 34 into the gasinflow chamber 32 as indicated by arrows from the top to the right inFIG. 3. The gas further flows through the heat exchanging unit 17 asindicated by arrows from the right to the left in FIG. 3, and enters thegas migration chamber 29. The gas migrates in the gas migration chamber29 from the left to the right of FIG. 1 and then flows though the heatexchanging unit 17 to the gas outflow chamber 33. The gas in the gasoutflow chamber 33 flows out of the gas outflow port 35.

In the course of the aforementioned flow of the gas, the thermal mediumexchanges heat with the gas. If cooling water is applied to the thermalmedium and air is the gas, the air is cooled by the cooling water as aresult of the heat exchange. The cooled air is extracted from the gasoutflow port 35.

Details of the heat exchanging unit 17 will be described hereinafterwith reference to FIGS. 4-7.

The plates 21 are configured to increase contact area with respect tothe flowing gas and serve as cooling (or heating) fins. As mentionedabove, the gas flowing around the plates 21 is as a whole directed in adirection from one end to another end of each of the plates 21. Thedirection is shown as from the right to the left in FIG. 3 and as fromthe top to the bottom in FIG. 5. Throughout the specification andclaims, “a flow direction” with respect to each of the plates 21 isdefined as a direction along which the gas is made to flow andcorrespondent with a direction from one end to another end of each ofthe plates 21.

Each of the plates 21 is provided with a plurality of openings 36 whichfixedly support the tubes 18. The openings 36 are arranged in aplurality of rows which are perpendicular to the flow direction andarranged at even intervals. Positions of the openings 36 in each row arelaterally deviated from positions of the openings 36 in the adjacent rowby half of a pitch of the openings 36, thereby the openings 36 in eachrow are disposed adjacent to gaps between the openings 36 in theadjacent row. The half of the pitch is not greater than the diameter ofthe openings 36.

Collars 37 respectively stand around the openings 36. The collar 37serves as a spacer for keeping gaps toward an adjacent plate 21. Thecollar 37 further serves to transmit heat between the plate 21 and thetube 18.

Respective spaces among the openings 36 are cut or punched out toproject from one side of the plate 21 as shown in FIGS. 4 and 7. Theseprojections form a group in each space and each projection is formed tobe a shape of a bridge having legs at both ends and a flat top spanningthe legs as shown in FIG. 6. Bridges 39, 40, 41 at the middle of eachgroup are directed perpendicular to the flow direction and arranged in arow along the flow direction. Upstream of the bridges 39, 40, 41 withrespect to the flow direction, just downstream of one opening 18, a pair38 of sub-bridges 38 a, 38 b is formed. The sub-bridges 38 a, 38 b arearranged to be symmetrical with respect to the center of the pair andare slanted from the center to both sides of the pair 38 toward the flowdirection. Similarly, downstream of the bridges 39, 40, 41, justupstream of another opening 18, a pair 42 of sub-bridges 42 a, 42 b isformed, however, contrary to the aforementioned sub-bridges 38 a, 38 b,the sub-bridges 42 a, 42 b are slanted from both sides to the center ofthe pair 42 toward the flow direction.

Arrangement of the tubes 36 respectively inserted in the openings 36defines a plurality of serpentine flow lines 44 among the tubes 36, asindicated by serpentine arrows in FIG. 5. The bridges 39, 40, 41 and thesub-bridges 38 a, 38 b, 42 a, 42 b are arranged along and perpendicularto the serpentine flow lines 44. Further, the legs of the bridges 39,40, 41 and the sub-bridges 38 a, 38 b, 42 a, 42 b are substantially inparallel with the serpentine flow lines 44.

The plate 21 is provided with ribs 43 projecting on the same side as thebridges as shown in FIG. 7. The shape of the ribs 43 is not limited tobut can be a triangular sectional shape. The ribs 43 run at respectivemiddles of the rows of the openings 18.

When assembling the plates 21 and the tubes 18, one of the plates 21 ishandled so that the tubes 18 are inserted to the respective openings 36thereof. The plates 21 are one by one put under assembly to be combinedwith the tubes 18. When one of the plates 21 abuts on another of theplates 21 with interposing the collar 37, the gap therebetween isregulated by the collar 37 serving as a spacer. After all of the plates21 and the tubes 18 are assembled, the tubes 18 are broadened so as tofix the tubes 18 with the plates 21.

Thereby, the tubes 18 and the plates 21 are combined to form the heatexchanging unit 17. The assembled heat exchanging unit 17 is combined inthe cylinder 14.

The heat exchanging unit 17 exchanges heat in accordance with thefollowing manner.

The gas subject to the heat exchange, such as air to be cooled, is madeto flow from the top to the bottom in FIG. 5. When the gas goes aroundany of the tubes 36, the gas tends to turn aside around an upstream facethereof. Since the sub-bridges 42 a and 42 b in the upstream stand thereso as to conduct the flow, the flow of the gas is smoothly branched intoright and left streams. Then the right stream is conducted by thesub-bridge 38 a of another group of bridges at the right and thedownstream, and the left stream is conducted by the sub-bridge 38 b ofthe other group of bridges at the left and downstream. The streams arerespectively merged with the other adjacent branched streams. Thesemerged streams are then further branched by the lowermost sub-bridges 42a and 42 b of the current bridge group. Therefore, the streams of thegas are respectively faired along the serpentine flow lines 44.

In general, gas flowing among cylindrical bodies such as the tube 18tends to form stagnation around downstream faces of the cylindricalbodies, however, the faring effect of the bridges prominently reducesthe stagnation. Further, since the streams of the gas just downstream ofthe tube 18 receive force in lateral directions by the ribs 43, thestagnation is further reduced. Reduction in the stagnation improvesefficiency of heat exchange of the heat exchanging unit 17.

The streams of the gas further receive force in a directionperpendicular to the plates 21 (perpendicular to a paper face of FIG. 5)from the bridges 38-42 and the ribs 43 to three-dimensionally fluctuate.Therefore contact length of the gas with the plates 21 increases andhence efficiency of the heat exchange further increases.

The ribs 43 may be formed not of continuity as mentioned above but ofdiscontinuity. For example, merely portions just downstream of the tubes18 may be formed to project but portions just downstream of the bridges38-42 may not be projected. Moreover, the ribs 43 maybe formed in pairedparallel rib shapes or half-round sectional shapes, or any othermodifications may be applicable.

Further, the bridges may be formed in other shapes, such as arch shapes.Any bridge between the sub-bridges 38, 42 may also be divided in a pairof sub-bridges like as the sub-bridges 38, 42.

Although the invention has been described above by reference to certainembodiments of the invention, the invention is not limited to theembodiments described above. Modifications and variations of theembodiments described above will occur to those skilled in the art, inlight of the above teachings.

1. A heat exchanger for exchanging heat with gas made to flow in a flowdirection, the heat exchanger comprising: a plurality of plates eachhaving a first side and a second side; a plurality of tubes configuredto conduct a thermal medium, the tubes penetrating the plates and beingarranged in parallel with each other and on a plurality of planesperpendicular to the flow direction, wherein the tubes on each plane aredisposed adjacent to gaps between the tubes on any of adjacent planes soas to form a plurality of serpentine flow lines among the tubes; and aplurality of bridges projecting on the first sides of the plates, thebridges being respectively arranged to be perpendicular to theserpentine flow lines.
 2. The heat exchanger of claim 1, wherein each ofthe bridges includes a pair of legs at both ends to be arranged alongthe serpentine flow lines.
 3. The heat exchanger of claim 1, furthercomprising ribs projecting on the first sides of the plates and runningat respective middles of the planes.
 4. A heat exchanger for exchangingheat with gas made to flow in a flow direction, the heat exchangercomprising: a plurality of plates each having a first side and a secondside; a plurality of tubes configured to conduct a thermal medium, thetubes penetrating the plates and being arranged at an even pitch inparallel on a plurality of planes perpendicular to the flow direction,wherein the tubes on each plane are respectively deviated in a lateraldirection with respect to the tubes on any of adjacent planes by half ofthe pitch of the tubes and the half of the pitch is not greater thandiameters of the tubes; and a plurality of bridges projecting on thefirst sides of the plates, the bridges being respectively arranged to beperpendicular to the serpentine flow lines.
 5. The heat exchanger ofclaim 4, wherein each of the bridges includes a pair of legs at bothends to be arranged along the serpentine flow lines.
 6. The heatexchanger of claim 4, further comprising ribs projecting on the firstsides of the plates and running at respective middles of the planes. 7.A heat exchanger for exchanging heat with gas made to flow in a flowdirection, the heat exchanger comprising: a plurality of plates eachhaving a first side and a second side; a plurality of openings formed onthe plates and arranged in a plurality of rows perpendicular to the flowdirection, wherein the openings in each row are disposed adjacent togaps between the openings in any of adjacent rows; a plurality of bridgegroups respectively projecting on the first sides of the plates andbeing disposed at the gaps, each of the bridge groups including aplurality of bridges perpendicular to the flow direction and arranged ina row along the flow direction, a first pair of sub-bridges disposed onan upstream end of the row with respect to the flow direction andslanted from a center to both sides of the first pair toward the flowdirection, and a second pair of sub-bridges disposed on a downstream endof the row with respect to the flow direction and slanted from bothsides to a center of the second pair toward the flow direction; and aplurality of tubes configured to conduct a thermal medium, the tubesrespectively penetrating the openings.
 8. The heat exchanger of claim 7,wherein the openings are arranged at an even pitch in each row and ahalf of the pitch is not greater than diameters of the tubes.
 9. Theheat exchanger of claim 7, wherein each of the bridges and sub-bridgesincludes a pair of legs at both ends to be arranged along flow lines ofthe gas directed by the tubes.
 10. The heat exchanger of claim 7,further comprising ribs projecting on the first sides of the plates andrunning at respective middles of the rows of the openings.